An electronic reader includes a storage unit configured for storing files and a processor. The processor includes a file display control module, a first file creating module and a second file creating module. The file display control module is configured for obtaining and displaying the files opened by user input. The first file creating module is configured for creating temporary files recording the comments and the amended sections of the opened files in response to user input. Each of the temporary files corresponds to one of the opened files. The second file creating module is configured for combining contents of the temporary files into a file. The contents of the temporary files are arranged in the file according to a predetermined rule if the formats of the temporary files are the same.